<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<style type="text/css">
			.content{
			  width: 100%;
			  margin: 0 auto;
			}
			.content img{
				display: block;
				max-width: 100%;
			}
		</style>
	</head>
	<body>
		<!--<div class="content">
			<img src="images/10.jpg" 
				srcset="images/10.jpg 480w ,images/11.jpg 800w,images/12.jpg 1600w",
				sizes="(min-width:800px) calc(100vw -30rem),100vw" 
				alt="prime-research"/>
				<!--sizes="100vw" 默认的-->
		<!---</div>-->
		
		<div class="content">
			<picture>
				<source srcset="images/11.jpg" media="(min-width:50em)"/>  
				<source srcset="images/10.jpg" media="(min-width:30em)"/>  
				<img src="images/1.png" alt=""/>
			</picture>
		</div>
		
	</body>
</html>
